1. Field of the Invention
The present invention relates to a balancing device for a reciprocating engine.
2. Description of the Prior Art
An engine becomes known in, for instance, a Japanese Patent Unexamined Publication (Kokai) No. Hei.9-210135 which is constructed such that balance shafts each provided with counterweights for canceling a secondary vibromotive force generated by a piston are provided so as to extend below a crankshaft and that the rotation of the crankshaft is transmitted to the balance shafts via a chain/sprocket mechanism.
In a conventional engine with a balancing device like this, it is constructed such that the rotation of a crankshaft is transmitted to sprockets provided individually on a rotor of a lubricating oil pump and one of the balance shafts via a common chain.
On the other hand, in the chain/sprocket mechanism, a chain tensioner is inevitable for automatically adjusting the tension of the chain. In a construction as described above, however, in which the sprockets for the crankshaft, balance shaft and lubricating oil bump are disposed in a triangular arrangement, the chain tensioner has to be disposed to project sideward, and this hinders the engine from being compactified.